Cleaning hard surfaces, such as kitchen, bathroom, floor and/or window surfaces, is a cumbersome activity. The dirt, soil and/or stains deposited on such surfaces, varies from for instance, but not limited to, lime scale and soap scum on bathroom surfaces, to burnt on oil on cooker tops, to algae on windows and mud on floors.
Brushes, wipes, cloths and scouring pads are commonly used to achieve improved cleaning, but their use involves substantial physical activity. Detergent compositions, are generally used to loosen or dissolve the dirt, soil and/or stains.
High pressure water jet cleaning tools are sometimes used outdoors to clean surfaces, while steam devices are available for cleaning indoors. High pressure water jets use a lot of water for cleaning, which is less preferable indoors, while the steam devices result in high temperature and humidity inside the house, which is also not appreciated by the consumer.
Small scale water jet devices have been disclosed in the art. FR-B-1108989 discloses a process to clean a substrate by subjecting the substrate to an air-water spray generated by a spraying means comprising an air passage and a water passage.
US 2002/189641 discloses a device for cleaning a soiled surface, the device comprising a feed water container and an air compressor in communication with the spray nozzle comprising a water passage and an air passage.
Both of the above mentioned devices provide an air water spray that is mixed inside the device. The disadvantage of such system is that the water flow cannot be reliably regulated because the air pressure goes against the water flow direction. This is especially problematic when a low water-to-air ratio (for instance in water:air ratios of less than 1:9) is required or a low water flow-rate is used. The nozzles of the prior art are generally not suitable for this purpose.
A novel air-water jet device is described in our co-pending application PCT/EP2009/050869 (published as WO2009/103595). This device provides a small and powerful air-water jet that uses only small volumes of water for cleaning and a reliable water flow-rate independent of the air pressure, because of the external mixing of air and water, compared to the internal mixing of other devices.
It is an object of the present invention to provide easier cleaning of hard surfaces.
It is a further object to provide a process for cleaning hard surfaces using an air-water jet.
It is yet a further object to provide a process for cleaning hard surfaces using a device having relatively low water flow rate.
Surprisingly it has been found that an external mix air-water jet device may be used for cleaning hard surfaces.